Variations in species-specific root and leaf traits
The morphological and chemical traits of the green leaves varied considerably across the 15 tree species (Table 1). The largest variations in morphological and chemical traits were obtained for LTD (coefficient of variation (CV) = 75%, ranging from 0.02 g cm-3 of Liriodendron chinense to 0.15 g cm-3 of Pinus elliottii ) and green leaf P concentration (CV = 35%, ranging from 0.6 mg g-1 ofP. elliottii to 1.9 mg g-1 of Quercus fabri ), respectively. For senesced leaves, the litter N and P concentrations showed approximately 4-fold variation among species, ranging from 5.7 mg g-1 of P. elliottii to 21.1 mg g-1 of Q. fabri for N concentration, and from 0.2 mg g-1 of Schima superba to 1.0 mg g-1 of Q. fabri for P concentration. There were no significant differences in green and senesced leaf traits between the AM and ECM species. The largest variation in absorptive roots was BI (CV = 67%, ranging from 1.1 of Cinnamomum camphora to 12.8 ofQ. fabri ). Compared to ECM species, the roots of AM species had larger diameters and ARL, higher N and P concentrations, and lower BI (Table 1).